A light emitting device capable of performing signal electric current
write-in operations at high speed and without dispersion in the
characteristics of TFTs structuring pixels influencing the brightness of
light emitting elements is provided. The gate length L of a transistor in
which an electric current flows during write-in of a signal electric
current is made shorter than the gate length L of a transistor in which
electric current supplied to EL elements flows during light emission, and
high speed write-in is thus performed by having a larger electric current
flow than the electric current flowing in conventional EL elements. A
converter and driver transistor (108) is used for signal write-in. By
using the converter and driver transistor (108) and a driver transistor
(107) when supplying electric current to a light emitting element during
light emission, dispersion in the transistor characteristics can be made
to have less influence on brightness than when using a structure in which
write-in operations and light emission operations are performed using
different transistors.